#ifndef _GETOPT_H
#define _GETOPT_H

#ifdef __cplusplus
extern "C" {
#endif 

    /* For communication from `getopt' to the caller.
     When `getopt' finds an option that takes an argument,
     the argument value is returned here.
     Also, when `ordering' is RETURN_IN_ORDER,
     each non-option ARGV-element is returned here.*/

    extern char* optarg;

    /* Index in ARGV of the next element to be scanned.
     This is used for communication to and from the caller
     and for communication between successive calls to `getopt'.

     On entry to `getopt', zero means this is the first call; initialize.

     When `getopt' returns -1, this is the index of the first of the
     non-option elements that the caller should itself scan.

     Otherwise, `optind' communicates from one call to the next
     how much of ARGV has been scanned so far.*/

    extern int optind;

    /* Callers store zero here to inhibit the error message `getopt' prints
     for unrecognized options.*/

    extern int opterr;

    /* Set to an option character which was unrecognized.*/

    extern int optopt;

    /* Describe the long-named options requested by the application.
     The LONG_OPTIONS argument to getopt_long or getopt_long_only is a vector
     of `struct option' terminated by an element containing a name which is
     zero.

     The field `has_arg' is:
     no_argument(or 0) if the option does not take an argument,
     required_argument(or 1) if the option requires an argument,
     optional_argument(or 2) if the option takes an optional argument.

     If the field `flag' is not NULL, it points to a variable that is set
     to the value given in the field `val' when the option is found, but
     left unchanged if the option is not found.

     To have a long-named option do something other than set an `int' to
     a compiled-in constant, such as set a value from `optarg', set the
     option's `flag' field to zero and its `val' field to a nonzero
     value (the equivalent single-letter option character, if there is
     one).For long options that have a zero `flag' field, `getopt'
     returns the contents of the `val' field.*/

    struct option
    {
#if defined (__STDC__) && __STDC__
        const char* name;
#else
        char* name;
#endif
        /* has_arg can't be an enum because some compilers complain about
         type mismatches in all the code that assumes it is an int.*/
        int has_arg;
        int* flag;
        int val;
    };

    /* Names for the values of the `has_arg' field of `struct option'.*/

#define no_argument 0
#define required_argument 1
#define optional_argument 2

    extern int getopt_long(int argc, char* const* argv, const char* shortopts, const struct option* longopts, int* longind);
    extern int getopt_long_only(int argc, char* const* argv, const char* shortopts, const struct option* longopts, int* longind);
    /* Internal only.Users should not call this directly.*/
    extern int _getopt_internal(int argc, char* const* argv,
        const char* shortopts,
        const struct option* longopts, int* longind,
        int long_only);
    extern int
        getopt(int argc,
            char* const* argv,
            const char* optstring);

#ifdef __cplusplus
}
#endif 

#endif /* _GETOPT_H */ 